DUP advisers were heavily involved in decisions to delay the introduction of RHI cost controls, a former adviser has claimed.

During his second day of evidence to the RHI Inquiry yesterday, ex-DUP adviser Timothy Cairns, who worked with former enterprise minister Jonathan Bell, claimed other party advisers were closely involved in decisions to delay the introduction of RHI cost controls.

And he said he mentioned this during a conference call which included DUP leader Mrs Foster in December 2016.

The 44-year-old said in June 2015 he was "directed" by adviser Timothy Johnston, now the DUP's chief executive, to liaise with senior adviser Dr Andrew Crawford over the RHI scheme.

He said Mr Johnston "shut the conversation down" and shortly afterwards the call ended.

Mr Cairns said Mr Bullick later contacted him to say that call was the first time Mr Johnston's name had been mentioned in connection with the RHI scheme.

In his written evidence, Mr Cairns said Mr Bullick told him Mr Johnston "was uncomfortable with my discussion of the June 2015 meeting, as up until that point he was adamant that he had played no role in RHI".

"However, my revelation had undermined his position," he said.

In an interview with Mr Nolan during the same programme as Mr Bell's claims were broadcast, Mrs Foster said she had no knowledge of her special advisers' roles in connection with RHI.

Mr Cairns said: "Either she had discounted what I said.. or she didn't then mention it in the interview when asked... or maybe she just forgot the telephone call immediately, I don't know."

The former special adviser agreed with inquiry counsel Donal Lunny that that the DUP's strategy led to enterprise officials agreeing a later closure date than they wanted.

But Mr Cairns said officials could also have objected.

"There was no pressure put on the officials," he said.

Responding to claims that DUP special advisers behaved as if they and enterprise officials were on opposing teams, Mr Cairns said: "If anybody felt we were on different teams, (I would have said) let's get on the same team again".

The inquiry will hear oral evidence from Dr Crawford today. It will be the second time he has given evidence.